Although this invention is not limited to disinfecting any particular enclosures, it is primarily useful to disinfect structures such as poultry houses. Poultry raised for food are grown in large, low silhouette houses. They are grown from hatchlings in the poultry house and removed only when it is time to slaughter and pack them for commerce.
When a poultry house is emptied of the poultry being grown there, it is necessary to clean it thoroughly and to treat it with a biocide. Manure is physically removed and the interior of the poultry house is cleaned with water and then disinfected by spraying its interior with a very strong and effective liquid biocide in a manner such that all surfaces within the poultry house are treated. One suitable biocide is an aqueous solution of formaldehyde and methanol. When the poultry house is sprayed, it must be isolated for a time sufficient for the biocide to dissipate. During the entire disinfecting procedure and until the biocide dissipates, personnel must not be exposed to the biocide. Although in the past personnel wearing protective clothing would literally enter the poultry houses to be disinfected and spray the interior by hand, government regulations and common sense have caused that practice to be discontinued.
One suitable apparatus for spraying the interior of a poultry house is described in U.S. Pat. No. 5,489,066 issued to Michael A. Oldham. The Oldham patent discloses a system which includes a spray vehicle on which a manifold having spray nozzles is mounted. The manifold is connected to a hose to supply biocide to the spray nozzles, and the hose is reeled onto a spool during the spraying procedure so that the vehicle is drawn through the poultry house to be sprayed from one end to the other whereby no personnel have to be within its interior during the spraying procedure.
When problems are encountered during the interior spraying of a poultry house, there is great difficulty involved in solving them. Personnel cannot enter the house for such simple tasks as moving a spray vehicle that got hung up on an interior column or to place it in its proper position if it veers off its intended path of travel through the house. Sometimes it is necessary to discontinue the spraying procedure and to let the biocide dissipate before the house can be entered which, of course, delays the disinfecting process so that the cycle of raising poultry is interrupted. The major problems encountered during a disinfecting procedure are that the spray vehicle gets caught on a column or other part of the structure or that it encounters a curb or the like on the floor of the house that it cannot be pulled over or that it veers off its intended path so that some portions of the interior of the poultry house gets sprayed more thoroughly than other portions. As mentioned in the Oldham patent, the vehicle must track properly as it is pulled through the poultry house if spraying is to be properly accomplished. The Oldham patent discloses a device that tracks accurately by having a sled or skid on the leading part of the vehicle and wheels on the back. In accordance with the Oldham disclosure, in order for a spray vehicle to track accurately it is necessary to have a sled at the leading part of the vehicle and wheels at the back.